BRCA1 and BRCA1 (/ˌbrækəˈwʌn/) are a human gene and its protein product, respectively. The official symbol (BRCA1, italic for the gene, nonitalic for the protein) and the official name (breast cancer 1, early onset) are maintained by the HGNC. Orthologs, styled Brca1 and Brca1, are common in other mammal species. BRCA1 is a human tumor suppressor gene (to be specific, a caretaker gene), found in all humans; its protein, also called by the synonym breast cancer type 1 susceptibility protein, is responsible for repairing DNA.BRCA1 and BRCA2 are normally expressed in the cells of breast and other tissue, where they help repair damaged DNA or destroy cells if DNA cannot be repaired. They are involved in the repair of chromosomal damage with an important role in the error-free repair of DNA double-strand breaks. If BRCA1 or BRCA2 itself is damaged by a BRCA mutation, damaged DNA is not repaired properly, and this increases the risk for breast cancer. Thus, although the terms ""breast cancer susceptibility gene"" and ""breast cancer susceptibility protein"" (used frequently both in and outside the medical literature) sound as if they describe an oncogene, BRCA1 and BRCA2 are normal; it is their mutation that is abnormal.BRCA1 combines with other tumor suppressors, DNA damage sensors, and signal transducers to form a large multi-subunit protein complex known as the BRCA1-associated genome surveillance complex (BASC). The BRCA1 protein associates with RNA polymerase II, and through the C-terminal domain, also interacts with histone deacetylase complexes. Thus, this protein plays a role in transcription, DNA repair of double-strand breaks ubiquitination, transcriptional regulation as well as other functions.Methods to diagnose the likelihood of getting cancer of a patient with mutations in BRCA1 and BRCA2 were covered by patents owned or controlled by Myriad Genetics. Myriad's business model of offering the diagnostic test exclusively led from Myriad being a startup in 1994 to being a publicly traded company with 1200 employees and about $500M in annual revenue in 2012; it also led to controversy over high prices and the inability to get second opinions from other diagnostic labs, which in turn led to the landmark Association for Molecular Pathology v. Myriad Genetics lawsuit.